Fluid flow control apparatus



March 23, 1954 I HERMANSON 2,672,880

FLUID FLOW CONTROL APPARATUS Filed Aug. 50, 1951 I I I i 2 8 NF) 'I:%-m g p m ATTO RNE' Y Patented Mar. 23, 1954 signor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application August so, 1951, Serial No. 244,418

g 9 Claims.

This invention is concerned with control of flow of fluid from various containers and more particularly with controlling the quantities of fuel in various containers in an aircraft with respect to each other in order to control the center of gravity of the aircraft. It is therefore an object of this invention to devise a new and improved ratio control for controlling the flow fuel between several tanks.

Another object of the invention is to devise a small, light-weight ratio control for controlling the fiow of fuel between aircraft fuel tanks.

A further object of the invention is to devise a ratio control for controlling the flow of fuel between'aircraft fuel tanks which may be manuually adjusted. I

vA further object of the invention is to devise a ratio control for controlling the flow of fuel between aircraft fuel tanks in which the ratio may be manually varied during flight.

A further object of the invention is to devise a ratio control for controlling the flow of fuel between aircraft fuel tanks which uses a simple reversible pump.

Briefly, the invention consists of utilizing capacitive type tank units in which the capacitances of the tank units vary withchange in fuel quantity in the tanks in which the tank units are placed due to the difference in dielectric constant between the fuel and-the air in the tanks above the fuel.

- The signals from a pair of tank units are compared to control the operation of a reversible pump in the transfer pipe between the tanks.

It is often desired, inorder to keep the center of gravity of a craft within specified limits, to;

have one tank drain more rapidly than a second tank. This may be, for example,when one tank is larger than the other tank. Therefore, a sig-' nal from a fixed capacitor is added to the signal the tank units while decreasing the effective Signal from the other tank unit and still keep the resultant signals equal. When the network .is

balanced, the pump is not energized. When the network is sufficiently unbalancedythe pump.

causes transfer of fuelfrom one tank to the'other tank until the network is rebalanced.

. For a more complete discussion of theinvention reference is hadto the following detailed description taken in conjunction-with companying drawing in which:

theinvention...

th ac- The 'single'flgur'e a schematic-diagramof In the drawing, the network I0 controls the I operation of an amplifier I I to control the energization of motor and pump 9 in the transfer.

line between tanks 5| and 60. Pump 9 isa reversible pump, that is, it can pump in either direction, depending on the phase of the voltage energizing the motor.

Network Ill is energized by a transformer I6- having a primary II energized from a source of voltage, not shown. Transformer I6 has a sec-- ondary 20 having a tap 2|. A balancin potenpurposes subsequently to be described. Potentiometers 22 and 23 are connected in parallel between the wiper arm I9 of potentiom-- eter I8 and tap 2| .of secondary 26 while poten tiometers 24 and 25 are connected in parallel across the lower portion of transformer secondary 20. Tap 2| of transformer secondary 20 is.

connected to input terminal 26 of amplifier II through conductors 21, 30, and 3 I.

A fixed capacitor 32 is connected to wiper arm 33 of potentiometer 22 through conductor 34. Fixed capacitor 32 is also connected to the other.

input terminal 35 of amplifier II through conductors 36, 31, and 4|.

connected to wiper arm 43 of potentiometer 24 through conductor 44. Fixed capacitor 42 is also. connected to the input terminal 35 of amplifier I I through conductors 45, 31, and 4 I.

A tank unit 46, having an inner electrode 4'! and an outer concentric electrode 50, is shown positioned in a. tank 5|.

potentiometer 23 through conductor 53. The inner electrode 41 of tank unit 46 is connected to input terminal 35 of amplifier I I through conductors 54 and 4 I.

A tank unit 55, having an inner electrode 56 and an outer concentric electrode 51, is shown positioned in a tank 60. Outer electrode 51 of tank unit 55 is connected to wiper arm 6| of potentiometer 25 through conductor 62. Inner electrode 56 of tank unit 55 is connected to input terminal 35 of amplifier II through conductors 63 and 4|.

Tanks SI and send fuel to the engine,not

shown, through pipes SI and 92, respectively.

Wiper arm I9 is manually adjusted along potentiometer I8 in orderto get equal voltagesacross potentiometers 22, i3, 24, and 25.

Wiper arms 33, 43, 52, and 6 I of potentiometers" 22, 24, 23, and 25 respectively are connected toa manually adjustable knob 64 through mechani- A fixed capacitor 42 The outer electrode till of tank unit 46 is connected to wiper arm 52 ofcal connections 65 and 66. The purpose of manual knob 64 is to control the comparative quantities of fuel in the tanks in order that the center of gravity, oi the remainswithin a certain desired rqlgellapdrzpn'ewents the craft iirmnsbe coming unbalanced upon consumption of fuel by the engine.

Movement of knob 64 in a clock- Wise on, as shown in the drawing, lowers wiper arms 52 and 6| or potentiometemsnlandpy 25, respectively, as it simultaneouslyraisesthe wiper arms 33 and 43 of potentiometers jnand r 24, respectively. Such a mnvem'en'tof 311025116415 reduces the potential across tank 46 "whil"' raising the potential across fixed capacitor 32.

Thus, if the capacitances ofitan-k unit 48 mm capacitor 32 are equal, the resultant signal from tank unit 46 and capacitor 32 remains the same since the signal supplied to amplifier II, is in each case "dependent upon: the product of the voltage" and "thecapacitance." The downward movement or wiperarm- Hof potenti'ometerli increases the-signal from tank 55 while the movement of", wiperyarm upwardly along potenti ometer 24 reduces-the signal from capacitor 4-2.

However, with tank unit 55*andcapacitor 42 havingcqual capacitances the resultant signal from tank unit 55 and fi xed capacitor 42 remains the-same.

Ifth'e network is designed so that when tanks H and 66- are *fuli thecapacitances of capacitor 32 andtankunit 46-are equal and the capacitances oi' capacitor *4! and tank-unit 55' are equal' and the-signal indications irom capacitor 32 and tankunit 46 are-equal-and oppositein phaseto the slnalmdieations from capacitor Hand-tank unit W."'-movement of manual; knob 64 cannot throw the network out of mal'anceuntil fuel is used.

The si'e'nal indications may be equalizedlayerijustihg wiper i60n-potentiometer 16, This makes itpossibletmsct knoblkinadvancaso that the desired-ratio of: fuel w-iilhie-maintained betweenmpadtors m andlzwere not: used the unbalance at the metwork. duemto movement .aof. knob 64i would beastgreat as the.- percentage ofidiflexence inmoltaze change.- acrossz theattwo tankunits. 1 By.

tbmusermf capacitors n ;;and 42,, however, the:

network"unhalanceaisaappreciablydecreasedi It im flhm;mkg mt gi h t m is then possible, by manually nmv'ingwiperwarm Ii! i-along. potentiometer 'I ii, to, ,rebalaime the .network-and to indicate: when; balancea is, again at:

tamed ma mannersubsequentiy to be described? lmienmovement of knob 1 64: causes unbalance; clockwisewmovement oi knob @64 results in the signals from capacitor 42: and; tank unit 551 She,

ingwgreaterthan; the signals from capacitor -18! and tank unit 46. Therefore, with amequal amin acre- (rt-fuel from, tank 5|, through; pine line 6| minals II, 12, and I3. Amplifier H may be any amplifier which is capable of being operated by a voltage signal of reversible polarity to reversiblyoperate. a mo tor in its output circula, Such an: amplifies, immmotoij iornbieafloni is shown,

for example, in the UptonPatent 'ZAZSISSi, as-

, signed to the same assignee as the present invent'ion. Output terminals II and 13 are connected to; teminals'ii'llklnd 16 respectively of the motor and pump, combination 9. Output terminal 12 oftheamplifier iscqm'iected to ground terminal, ilTiwhIIE terminal 1.520: the motor is connected to ground terminal will;

Indicator light 63 is connected to amplifier out,- put leld ll by 'confluctor 82 and also to ground terminal ,84 so as to light up upon amplifier ll being so'energized as to energize conductor 6|. Inthe same manner indicator light 81 is connected-tourmaline! output lead fl- 'by conductor "and also tdgrou'nd' terminal "96: a

Pump'l is connected to tank It by pipeline and to tanlr 69' by pipe -'l-ine-= T6 tocontrol the transferoffuelbetween the two tank's.

Whemnetworkflfiis balanced ampliile'r 4| a unenergized andmerther conductor 81 ducton energized. As a resultgunder btllki. ance conditions lights "and 61 are work ll is unbalaneed; amplifier" is energized and energizes either conductor 8* or conductor 85, thus lighting-up eithemlight 6t on-light- 8-1. Now "if manual knob" is moved -unbelancmg network lilpit is possible-to rebalance the now work by -moving" wiper arm IO along ter l8 until both lights 63 and 81 areOiT-i with the unbalance "c! the network as-previously described momma thesis-ital mm tank; unit 55 'decreases-moo'e l rapidly thc' 1 m from tank unitwupon cquatoflhetanls through pipes 6i and" SI tocausean unbalance or the networtand -energise amplifier-L t! pimm S operatesto transficn met tram tanh ii totem 60 until the network is again balanced'i: lit-this time theampliflenl t deaietgioedgdeeg the motor and" pump combination :6;

' then leaves tanks'in-iiequalcuantities until the change at signal-of tanklunitvfli withfzrespeet W1 c o se M -"madman: unit lt again; has

comes sumoiently i grout tor reeuergim and fromtank, throughapipeline sttheichangein signal: irom: tank a unit 55. is: proportionately work. to "to cause op r tion, cram-mine; it im a first direction.

u i s v arteheveweessteettei 46 and 55.

II and again energize the motor and-Mimi binationito tumtem additiomiiuel iromrtanhiil 1!: manuah 1mm fl issmoved 'counmrclockm simhzthatwiperc arms ll and 43 =01; pmentinmmis It and :4 are :lomered while simultaneously raise ingzthe wipumrmsxl! :andufi't ot potentiomdm zrandcifirtha 'o will he That isgthe maktromtank bewreaton Ir itis desixetbtmoontmhthw' quantities melamine minor: tanks. ma l. 01" "meaim'jhhcfi thmmmunm inw fl mm: 90131121 that! 1B1 fi ament: 1..mM sam at the controls on an aircraft and response .to the controls will remain approximately the same all through the flight because the center of gravity of the craft will remain relatively stationary. Also, adequate fuel flow to the engine is assured because the control of the comparative fuel quantities doesnot exist in the fuel lines to the engine but instead are placed in, the transfer line between the tanks and so fuel flow to the engine from one tank is not cut ofi whilethe circuit is being rebalanced.

While only a particular design of the invention has been shown, it is realized that modifications may be made by those skilled in the art and it is therefore to be understood that the scope of this invention is limited only to the extent of the appended claims.

I claim as my invention:

1. Fluid flow control apparatus comprising in combination: first capacitive means in a first container of fluid, the capacitance of said capacitive means being an indication of the quantity of fluid in the container; second capacitive means in a second container of fluid, the capacitance of said second capacitive means being an indication of the quantity of fluid in the second container; a first capacitor; a second capacitor; first, second, third and fourth sources of variable potential; means connecting said first capacitive means to said first source of potential such as to derive asignal therefrom; means connecting said second capacitive means to said second source of potential such as to derive a signal therefrom; means connecting said first capacitor to said third source of potential such as to derive a signal therefrom; means connecting said second capacitor to said fourth source of potential such as to derive a signal therefrom; means connecting said first and second capacitive means and said first and second capacitors together such that the signals from one of said capacitive means and one of said capacitors oppose the signals from the other of said capacitive means and the other of said capacitors; and means operated by the resultant signal controlling the comparative quantities of fluid in the containers.

2. Fluid flow control apparatus comprising in combination: first capacitive means in a first container of fluid, the capacitance of said capacitive means being an indication of the quantity of fluid in the container; second capacitive means in a second container of fluid, the capacitance of said second capacitive means being an indication of the quantity of fluid in the second container; first and second sources of variable potential;

means connecting said first capacitive means to said first source of potential such as to derive a signal therefrom; means connecting said second capacitive means to said second source of potential such as to derive a signal therefrom; means connecting said first and second capacitive means together such that the signal from said first capacitive means opposes the signal from said secon Lcapacitive means; means operated by the resultant signal controlling the comparative quantities of fluid in the containers; and means for simultaneously increasing the potential across one of said capacitive means and decreasing the potential across the other of said capacitive means.

3. Fluid flow control apparatus comprising in combination: first capacitive means in a first container of fluid, the capacitance of said capacitive means being an indication of the quantity of fluid in the container; second capacitive means in a second container of fluid, the capacitance of said second capacitive means beingan indication.

ond, third and fourth sources of variable poten-' tial means connecting said first capacitive means to said first source of potential such as to derive a signal therefrom; means connecting said sec-' ond capacitive means to said second source of potential such as to derive a signal therefrom; means connecting said first capacitor to said third source of potential such as to derive a signal therefrom; means connecting said second capacitor to said fourth source of potential such as to derive a signal therefrom; means connecting said first and second capacitive means and said first and second capacitors together such that the signals from one of said capacitive means and one of said capacitors oppose the signals from the other of said capacitive means and the other of said capacitors; means operated by the resultant signal controlling the comparative quantities of fluid in the containers; and means for simultaneously increasing the potential across one of said capacitive means and decreasing the potential across the other of said capacitive means.

4. Fluid flow control apparatus comprising in combination: first capacitive means in a first container of fluid, the capacitance of said capacitive means being an indication of the quantity of fluid in the container; second capacitive means in a second container of fluid, the ca ac itance of said second capacitive means being an indication of the quantity of fluid in the second container; a first capacitor; a second capacitor; first, second, third and fourth sources of variable potential; means connecting said first capacitive means to said first source of potential such as to derive a signal therefrom; means connecting said second capacitive means to said second source of potential such as to derive a signal therefrom; means connecting said first capacitor to said third source of potential such as to derive a signal therefrom; means connecting said second capacitor to said fourth source of potential such as to derive a signal therefrom; means connecting said first and second capacitive means and said first and second capacitors together such that the signals from one of said capacitive means and one of said capacitors oppose the signals from the other of said capacitive means and the other of said capacitors; means operated by the resultant signal controlling the comparative quantities of fluid in the containers; and means for simultaneously increasing the potentials across one of said capacitive means and one of said capacitors and decreasing the potentials across the other of said capacitive means and the other of said capacitors.

5. Fluid flow control apparatus comprising in combination: first responsive means in a first container of fluid, the impedance of said responsive means being an indication of the quantity of fluid in the container; second responsive means in a second container of fluid, the impedance of said second responsive means being an indication of the quantity of fluid in the second container; a first impedance; a second impedance; first, second, third and fourth sources of variable potential; means connecting said first responsive means to said first source of potential such as to derive a signal therefrom; means connecting said second responsive means to said second source of potential such as to derive a ageragesoi signal therefrom: means connecting said impedance to'said third" source of potentialfsucir of "potential such as to derive'a signal from; means connecting said and second responsive means and said and second "lin and derive a resnltantsignal; andmeans'op i ated by theresultantsi'gnal controlling the comparative quantities of-fiuidin the containers:

6. Fluid fiow control apparatus comprising in combination: first responsivemeans in" a" first container of fluid; the impedance ofsaid respon sive means being anindicatiomofthe quantity of fiuid in the container; second responsive means in asecond container offiuid, theimpedance of said second responsive-means being an indication of the quantity of fiuidin' the second, container; first and second sources of variable potential; means connecting saidfirst' responsive means to said first source of potentialsuch as to derive a signal therefrom; means connecting said second responsive means to" said second source of potential such as to' derive-a signal therefrom; means connecting-said first and second responsive means' suchthat the signal from said first responsive means opposes the signal from said second responsive means-and derive a resultant signal: means operated by theresultant signal controlling the" com arative quantities of fluid in the containers; and means for simultaneouslyincreasing the potential across one oi 'said responsive meansanddecreasing the potential across the other of said responsive means. I

'7. Fluid flow control apparatus comprising'in' combination: first responsivemeans in a first container of fluid; the 'impedancegof said responsive means being an' indication of'the quantityoi fluid in the container; second responsive means in, a" second container of fluid, the 'impedance'of saidfseeond responsivemeans" being an indication of'the quantity of fluid in the'secondcontainer; a first impedance: asecond pedance; first; second, third and tourthwsources or variable potential meansconnecting saiddiist responsive means to said first source of potential such as to derive a-signaltherefrom; means con necting said second responsive-means to saidsec and source of potential such as to derivea'siznal therefrom; means connecting said firstimped ance to said "third source of potential suchas .to derive-a signal therefrom; means connectingsai'd second impedance to said fourthsource otpoterrti'al such as to derive a signal therefrom; means 8* connecting" said first andsecond responsive means and said first andsecond impedancessuch that the signals from one" of said responsive means and one 01" 'said' impedanees the signals "from the other I of "said responsive means and the other of said impedances and derives resultant signal: means operated by the resultant signal controlling the comparative" quantities oi!" fluidin the containers; and'means for simuitane ously increasing the potentials "acrossoneof'said responsivemeans and oneof said impedances and decreasingthe potentials acrossthe otheror said responsive means and the other of said pedances.

8. Apparatus for controlling the clistribution of liquid between twotankaeomprising; wear-- pacitor in each tank themapacityof whichivaries proportionally to the' volume of liquid in the tank; a source or cyclically varying voltagescom nected tosaid capacitors for obtaining signals from said capacitors; electrical meansrespon'sivs to" the "relative magnitudes of the-"signals from said capacitors flow -control means controlled-by said "electrical means'for varying therelative voiumes oi 'the liquid in the tanksfor maintaining the relative volumes or liquid in the" tanks at' a' predetermined desired" value; and meanslor changing the desire value by the mag-s nitu'des -oi the signals" from the cap'aeitors inde pendentl-yof 2 changes in the capacities-of" the capacitors by varying the voltages aerosswaid capacitors.

9; Apparatus lorcontrolling the or liquid between two-tankspcomprisirig: a-re spoils-Ive means each "tank the impedanceot which" varies proportionally, to volume 1 or liquid in 'the tanks; a souree of voltages con-'- nected to said responsive means "for" obtainmg signals from said" responsive means: electrical means responsive" ta therelative magnitudes oi the signals from-said resp'onsivemeans: trol means-eontroll'ed by said electribalmeanl for varying the relative volumes ofitheliquid in the tanks-l for" maintaining the relative weeumes of liquid in-the-ata predetezmined desired value; and means tor changing desired value by varying the magnitudes: oi the signals: the responsivameamindependently ofi ch'amee in: the-impedanceavof the" v1 am meansby varying the voltages aemsl said iresponsi vemeansri' Rdezences. cited in thei fiie 0mm patents UNITED sra'ms "m'rams Number Name I Date 2,551,438 Johnson June-19,1 1951 2,563,280 Schafer et a1; A1191]; 1951 

